Rio Tinto’s Kennecott Copperton Concentrator has four grinding lines each consisting of one SAG mill feeding two ball mills in a closed circuit with a hydrocyclone battery (Figure 1). The aim of the ball mill / hydrocyclone circuit is to produce the optimum flotation feed particle size while maintaining grind throughput. The optimal operating point is a trade- off between throughput, recovery, and grinding cost. Copperton has recently focused on the role of the hydrocyclone battery and how to monitor the performance of each individual hydrocyclone. Variation in the performance of the grinding circuit flows through to the hydrocyclones and in many cases the hydrocyclones will report coarse material to the overflow when not operating as designed. Coarse material in the flotation feed reduces the economic performance of the concentrator through lower valuable mineral recovery and in extreme cases, through blocking of the flow path in the flotation cells.

The existing oversize detection system is installed on the combined hydrocylcone battery overflow line. Operationally, troubleshooting the cause of oversize is difficult and time consuming, resulting in considerable disruption to the flotation circuit before the offending hydrocyclone is taken offline. Copperton and CiDRA have installed a new technology for monitoring individual hydrocyclone overflow lines for coarse material discharge.